This disclosure relates to a gas turbine engine airfoil. In particular, the disclosure relates to a trailing edge cooling configuration having a particular arrangement of pedestals.
Coolant air exiting a turbine blade creates a mixing loss, which degrades the performance of a gas turbine. The mainstream air receives a loss as it brings the coolant air up to its velocity direction and speed. It is desired to minimize this mixing loss to improve the performance of the engine and lower the specific fuel consumption of the engine. From a turbine blade durability perspective it is desired to have all of the turbine blades in the rotor of one stage to have the same amount of cooling flow. This is because the cooling flow levels are one of the strongest drivers on blade metal temperature and the blade metal temperatures set the life of the part. The life of the turbine is determined by the failure of just one blade as opposed to many blades. The extra flow those blades are using comes at a performance penalty as it creates additional mixing losses. That extra coolant flow also bypasses the combustor and is not combusted, which is an additional loss to the system.
One type of turbine blade includes a trailing edge cooling passage having pedestals. In one example, elongated pedestals at the trailing edge exit are used to meter the flow of fluid from the trailing edge cooling passage into the gas path.